title: The effect of age and sex on metabolism and urinary excretion of antipyrine.
abstract: BACKGROUND
  Drug-metabolizing capacity is generally reduced in the elderly. The purpose of this investigation was to study antipyrine clearance and metabolite excretion in old subjects of both sexes.
  
  
  METHODS
  Saliva clearance of antipyrine and the production clearances of antipyrine metabolites were studied in young and elderly volunteers of both sexes. Seventy-six elderly subjects (mean age 81 years) were compared with a group of 24 young subjects (mean age 29 years).
  
  
  RESULTS
  After oral administration, salivary antipyrine clearance declined with age in both males and females, whether or not this variable was corrected for weight, and antipyrine half-life was significantly prolonged in elderly groups of either sex. The percentage urinary excretion of the antipyrine metabolites (hydroxymethylantipyrine, HMA; norantipyrine, NORA; and 4-hydroxyantipyrine, OHA) was reduced at 48 h in the elderly compared to young subjects by 23%, 31%, and 10%, respectively, in males, and by 41%, 41%, and 24%, respectively, in females. The formation clearance of HMA was reduced by 47% in males and by 52% in females. NORA clearance declined by 42 and 56%, respectively, in males and females. A decrease of 30% in males and 44% in females was observed in OHA clearance.
  
  
  CONCLUSIONS
  The findings suggest that aging leads to altered disposition of antipyrine in both males and females and that the main metabolic pathways of the compound are not different in the elderly.
authors.affiliation: Gastroenterology Unit, Hospital de Insalud, León, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Jorquera
authors.forename: M
authors.initials: M
authors.lastname: Almar
authors.forename: M
authors.initials: M
authors.lastname: Pozuelo
authors.forename: D
authors.initials: D
authors.lastname: Sansegundo
authors.forename: M
authors.initials: M
authors.lastname: González-Sastre
authors.forename: J
authors.initials: J
authors.lastname: González-Gallego
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism* / Q000652:urine; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000378:metabolism* / Q000652:urine; D000983:Antipyrine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000378:metabolism* / Q000652:urine; D001835:Body Weight; D000077553:Edaravone; D005260:Female; D016166:Free Radical Scavengers / Q000378:metabolism / Q000652:urine; D006207:Half-Life; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008297:Male; D008657:Metabolic Clearance Rate; D012463:Saliva / Q000378:metabolism; D012727:Sex Characteristics
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D016166:Free Radical Scavengers; C007983:4-hydroxyantipyrine; C031820:3-hydroxymethylantipyrine; D000077553:Edaravone; D000983:Antipyrine